1. Field of the Invention
The invention generally relates to surgery and more
specifically to body protecting or restraining devices for patients. The invention is an antisnoring device as well as a therapy for sleep apnea.
2. Description of Related Art
Including information disclosed under 37 CFR 1.97 and 1.98
An estimated twenty million people suffer from both snoring and sleep apnea. A single cause of both conditions is that the lower jaw and tongue fall back during sleep to partially block the airway. A known treatment is to use an oral appliance that repositions the lower jaw to prevent this partial blocking of the airway. This general category of devices is known as oral airway dilator appliances or mandibular repositioners.
When the airway is partially blocked, normal respiration requires and causes an increase in air speed through the airway. The increased air speed at the mouth and throat causes soft tissue of the uvula and soft palate to vibrate. This vibration causes noise that is known as snoring.
Sleep apnea results from a partial-to-complete blockage of the airway. Increased air speed through the airway will cause an increase in dynamic pressure and a corresponding drop in static pressure. The decreased static pressure tends to further draw back the lower jaw and tongue to further block the airway. This blockage can increase to the point of becoming complete, which at least temporarily interrupts breathing. Thus, sleep apnea also is known as obstructive sleep apnea. Typically, the blockage occurs in the area of soft palate or the base of the tongue. Those suffering from this condition can awaken with coughing and gasping as they try to restore normal breathing.
Oral airway dilator appliances help to open the airway by repositioning the lower jaw and tongue. These appliances prevent the jaw and tongue from falling back during sleep. Most oral dilator appliances are custom fabricated of hard plastics to fit to the upper and lower teeth. Such appliances are made in dental laboratories, based upon molds of the patient's teeth. They will have a separate upper and lower component. The two components or trays are joined together or otherwise interact to reposition the lower jaw. The repositioning takes place by a combination of opening the lower jaw and moving forward the lower jaw.
The lower jaw should be allowed to move during sleep to prevent general discomfort and specifically to avoid soreness in the temporomandibular joints. Custom fabricated appliances might employ swivels or hinges to join the upper and lower plates while allowing the lower jaw to move. Custom appliances tend to be costly because they require significant expertise by the dentist and by the laboratory.
An example of a currently available dental appliance is the elastic mandibular advancement (EMA) appliance that is the subject of U.S. Pat. No. 6,109,265 to Frantz et al. According to this patent disclosure, upper and lower trays are releasably joined together by a linear elastic band arranged to pull the jaw forward. Each tray carries a retention hook that engages an end of the elastic band. The upper hook is forward of the lower hook, such that the elastic band pulls the jaw forward when engaged on upper and lower retention hooks. The lower tray also carries a bite plane that opens the bite vertically. A limitation of this device is that because only elastic bands are applied to control front-to-back jaw position, the jaw muscles may suffer hyperactivity during sleep. As a result, the patient may continue to have disrupted sleep and discomfort.
A recently developed appliance for treating sleep disorder is the subject of U.S. Pat. No. 6,983,752 to Garabadian. According to this disclosure, separate upper and lower trays each carry a bite pad for separating the upper and lower jaws. In addition, the lower bite pad is anterior to the upper bite pad, such that the upper bite pad interferes with posterior movement of the lower bite pad to block the lower jaw from retracting. Each tray carries a pair of hooks for engaging an x-shaped elastic band. The elastic bands are adjustable on the hooks for selecting vertical and horizontal forces. Several limitations in the disclosed appliance are notable. The bite pads are relatively short in front-to-back dimension, which can induce the jaw to pivot and lead to muscle hyperactivity. The bite pads engage one another at vertical abutting surfaces that are substantially perpendicular to the front-to-back axis of the mouth, producing an abrupt stop that is likely to further induce muscle hyperactivity. Each bite pad impinges upon an occlusal surface of the opposite tray, which is conformed to the occlusal surface of the covered tooth. The roughness of this interaction interferes with jaw movement and might exacerbate sleep bruxism or clenching.
Another recently developed mandibular advancement device is the subject of U.S. Pat. No. 6,604,527 to Palmisano. The disclosure shows that upper and lower jaws respectively are fitted with upper and lower plates. The upper plate carries a depending side flange in the area near the posterior teeth, and the lower plate carries an upstanding side flange in a similar position. The side flange on the upper plate is posterior to the side flange on the lower plate and positioned to block the lower flange so as to prevent undesirable posterior movement of the lower plate. The positioning of the flanges to the side of the teeth offers several advantages: the lower jaw can close to a greater degree than possible with various other appliances; and the flanges can be vertically long so that the abutting surfaces continue to engage even if the jaw opens by a substantial amount. However, the length of the abutting surfaces can create an additional problem. The extremely long flanges may need to be contoured to the path of jaw movement, which can be complex. Further, locating the flanges to the side of the teeth can impose a limitation on lateral movement between the jaws, which may contribute to sleep bruxism.
Airway dilator appliances of the boil-and-bite variety can be fabricated of softer plastics and may be fitted to the patient in the dentist's office, without requiring the assistance of a laboratory. U.S. Pat. No. 5,868,138 to Halstrom shows an example of a boil-and-bite appliance that provides a swivel between upper and lower plates. Other boil-and-bite appliances provide a dental overlay that is molded to only the upper plate or only the lower plate. A single plate boil-and-bite appliance might employ a guide ramp and external shield. U.S. Pat. No. 5,092,346 Hays et al is an example of an upper plate dental overlay that employs a ramp structure that retains the lower jaw in a forward position. U.S. Pat. No. 6,092,523 to Belfer shows an upper plate dental overlay slidably coupled to a guide ramp that permits the lower jaw to move laterally.
As discussed above, sleep disorders such as sleep apnea and snoring are interrelated and may be found in the same patient. Likewise, the same patient may require treatment for sleep bruxism. Each of these conditions is subject to treatment by use of an oral appliance. Individual appliances for each condition may be impractical, due the frequency of the same patient needing treatment for more than one of these conditions or all of these conditions. Therefore, it would be desirable for a single oral appliance to address the combined needs for alleviating snoring, sleep apnea, and sleep bruxism.
An oral appliance worn during sleep should allow vertical and lateral jaw movement to discourage sleep bruxism. At the same time, an appliance should contribute to stability of the lower jaw to reduce snoring and prevent sleep apnea. It would be desirable to combine these characteristics in a single oral appliance.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the method and apparatus of this invention may comprise the following.